GitLost: We Tricked GitHub's AI Agent into Leaking Private Repos
IntroductionGitHub recently launched GitHub Agentic Workflows, pairing GitHub Actions (GitHub’s automation system for running tasks in response to repository events) with an AI agent backed by Claude or GitHub Copilot. Prompt injection is a class of attack in which an adversary hides malicious instructions inside the content read by an AI agent. That content causes the agent to follow those hidden instructions instead of the ones its operator intended.What are GitHub Agentic Workflows?GitHub Agentic Workflows let teams automate their interactions with code repositories using natural language.
- ▪IntroductionGitHub recently launched GitHub Agentic Workflows, pairing GitHub Actions (GitHub’s automation system for running tasks in response to repository events) with an AI agent backed by Claude or GitHub Copilot.
- ▪Prompt injection is a class of attack in which an adversary hides malicious instructions inside the content read by an AI agent.
- ▪That content causes the agent to follow those hidden instructions instead of the ones its operator intended.What are GitHub Agentic Workflows?GitHub Agentic Workflows let teams automate their interactions with code repositories using natura
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Attribution is not the same as permission. This drawer separates discovery metadata, excerpts, WeSearch-generated summaries, reuse status, and whether the publisher receives the visit. Nothing here claims a legal grant the publisher has not made.
Record
| Original publisher | Noma |
| Canonical URL | https://noma.security/noma-labs/gitlost-how-we-tricked-githubs-ai-agent-into-leaking-private-repos |
| Publication time | Tue, 15 Sep 2026 22:00:28 +0000 |
| Retrieval time | 2026-09-15T22:16:52.605Z |
| Last seen | 2026-09-15T22:16:52.605Z |
| Headline source | Publisher (no WeSearch rewrite) |
| Excerpt source | publisher body |
| Excerpt method | First ~120 words (~800 chars) of extracted publisher body, fair-use limited. |
| Summary | WeSearch · cerebras-chat (WeSearch summarizer) |
| Summary source text | contentText |
| Citation coverage | Summary is a WeSearch-generated derivative; primary citation is the original publisher URL. |
| Cluster | ubHpnn4JQY7y · 1 stories |
| Cluster logic | Grouped by semantic title/content similarity across sources within a rolling window. Same-publisher template collisions are excluded from coverage comparison. |
| Ranking reason | Story pages are not engagement-ranked. Hub feeds use recency, with optional source-diversified chronological ordering (cap consecutive stories per source). No personalized ranking. |
| Publisher visit | Yes — open original |
| Substitutes article? | No — link-out required for full text |
Rights status (four layers)
WeSearch handling by dimension
| Indexing | May the item be indexed (stored, ranked, made findable)? | Allowed |
| Snippet | May a short excerpt of the publisher's text be shown? | Allowed |
| AI summary | May WeSearch generate its own short summary of the article? | Limited |
| Retrieval / RAG | May the content be exposed for third-party retrieval-augmented generation? | Not asserted |
| Model training | May the content be used to train AI models? | Not asserted |
| Commercial reuse | May the content be reused commercially? | Not permitted |
Basis: Derived from the published RSS/Atom feed. Contact: [email protected]. Reviewed: 2026-07-24.
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Back to nomalabsGitLost: How We Tricked GitHub’s AI Agent into Leaking Private ReposSasi LeviJuly 6, 2026TL;DR: Noma Labs discovered a critical prompt injection vulnerability within GitHub’s new Agentic Workflows, allowing an unauthenticated attacker to silently pull data from private repositories by posting a crafted GitHub Issue in a public repository belonging to the same organization as the private repositories. Noma Labs named the vulnerability GitLost. Your browser does not support the video tag. IntroductionGitHub recently launched GitHub Agentic Workflows, pairing GitHub Actions (GitHub’s automation system for running tasks in response to repository events) with an AI agent backed by Claude or GitHub Copilot.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at Noma.
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